1. Field of the Invention
The present invention relates to shredded tobacco and a method of treating tobacco.
2. Description of the Related Art
Dryleaf tobacco and shredded tobacco obtained by shredding the dry leaf tobacco contain tobacco specific nitrosamines (hereinafter referred to as “TTSNAs”), which are typified by N′-nitrosonornicotine (NNN), N′-nitrosoanatabine (NAT), N′-nitrosoanabasine (NAB) and 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK), and polyphenols. These TSNAs and polyphenols are substances which are desired to be removed.
Many attempts have been made to remove TSNAs and polyphenols contained in shredded tobacco. For example, Jpn. PCT National Publication No. 2003-526345 describes a method of removing nitrosamines contained in tobacco by using supercritical carbon dioxide. Also, Jpn. PCT National Publication No. 2002-520005 describes a method of removing phenolic compounds in a tobacco material by treating the tobacco material with a phenol oxidizing enzyme.
However, neither of the methods described in Jpn. PCT National Publication Nos. 2003-526345 and 2002-520005 can reduce both TSNAs and polyphenols at the same time. Also, special equipment is required in the method described in Jpn. PCT National Publication No. 2003-526345 because an operation under high pressure is necessary in this method. In the method of Jpn. PCT National Publication No. 2002-520005, an enzymatic reaction is used and it is therefore necessary to control the temperature of the system at which enzymatic activity is retained, and many steps are required for the treatment.